DENTISTS VARIABILITY IN RESTORATIVE DECISIONS, MICROSCOPIC AND RADIOGRAPHIC CARIES DEPTH

Restorative and dental caries depth decisions were recorded for 5168 u nrestored approximal tooth surfaces by 17 dentists who worked in the s chool dental clinics of the North York (Ontario) Public Health Departm ent. Each dentist examined 15 pairs of experimental bitewing radiograp hs for which true caries depth had previously been determined by micro scopy of the sectioned teeth following production of the radiographs. The dentists independently recorded their restorative decisions and ra diographic caries depth perceptions. The relationship between the vari ation in the dentists' restorative decisions and their perceptions of caries depth based on a re-reading of the bitewings on the one hand, a nd true caries depth on the other was also examined. The percentages o f total variability in each dentist's restorative decisions attributab le to radiographic and to microscopic caries depth were estimated usin g regression analyses. Large variations were found among the 17 dentis ts' distributions of overall restorative and depth decisions. The rela tionship between microscopic caries depth and the dentists' restorativ e decisions was, understandably, less strong than that of the dentists ' radiographic perceptions of caries depth and restorative decisions. Relative to true caries depth, high numbers of false positive and fals e negative restorative decisions were made. Overall, 50% of the variab ility in the dentists' restorative decisions was explained by their pe rceptions of radiographic caries depth; however, among individual dent ists, the range was from 29% for one dentist to 69% for another. A muc h lower percentage of the overall restorative variation was explained by microscopic depth, 18%. Like the findings of the only two previous European studies that quantified the role of radiographs on clinical d ecisions, this study demonstrated that dentists' perceptions of dental caries depth using bitewing radiographs play a major but variable rol e in their restorative decisions for approximal tooth surfaces.